<!doctype>
<html>
	<head>
		<script>


function aa() {
	var a = 1;

	if(a == 1){
		var b = 2;
		alert(b);
	}else{
		alert(b);
	}
	alert(b);
}

aa();


		</script>
	</head>
	<body>
			
	</body>
</html>